It is known in the prior art that low density microcellular polymer foams can be prepared which are useful for foaming targets for inertial confinement fusion. For example, U.S. Pat. No. 4,430,451 (Young et al), discloses such a foam which is prepared from poly (4-methyl-l-pentene) and a bibenzyl solvent.
It is also known in the prior art how to prepare porous carbon from polyacrylonitrile (PAN) and other acrylonitrile-based materials. Examples of such porous carbon are disclosed in U.S. Pat. Nos. 4,439,349 (Everett et al) and 4,118,341 (Ishibashi et al) wherein acrylonitrile polymers are used in the preparation of porous carbon adsorbents. The porous carbon materials disclosed in these patents are characterized by high densities and extremely small pore sizes, and thus these materials offer great resistance to the flow of gases or liquids through them. Hence, they cannot be used successfully as catalyst supports in a catalytic flow reactor, or in other similar applications. It should also be noted that the prior art materials are not structural foams.
What is desired, therefore, is to develop a low density, microcellular carbon foam prepared from acrylonitrile-based materials which can be used successfully not only in the fabrication of inertial confinement fusion targets, but as a catalyst support, an absorbent, a filter, an electrode, and in a variety of other applications as well.